Valve mechanism for rock drills



Nov. 4, 1930. W. A. SMITH, SR.. L 7 1,730,725

VALVE MECHANISM FOR ROCK DRILLS Filed Dec. 14, 1928 [Ina will mZISmi flair.

THEIR ATTORNEY Patented Nov. 4, 1930 s'r TEs P ENT OFFICE q W ILLIA'M A. siurrn, SR, or EAsroN, PENNSYLVANTA, AND WILLIAM A. SMITH, an, or

rHILLIPsB RG, NEW JERSEY, ASSIGNORS T0 INGERSOLL-BAND coMrANY,';or JER- 'SEY crrY, NEw'JEnsEY, A CORPORATION or NEW JERSEY VALVE MECHANISM FbR ROCK DRILLS Application filed December 14, 1928.. Serial No. 325,987.

This invention relates to rock drills, but more particularly toa valve mechanism for distributing the pressure fluid to rock drllls of, thehammer type.

The objects of the invention are to obtain a heavy blow of the hammer piston against the working implement and to use the pressure fluid expansively so that the pressurefluid consumption for actuating the drill will be 10 held to a minimum.

Other objects will be in part obvious and in part pointed out hereinafter. a

In the drawings illustrating the invention and inwhich similar reference characters refer to similar parts,

, Figure 1 is a diagrammatic view in sectional elevation of a rock drill equipped with valve mechanism constructedin accordance with the practice of the invention and illustrating the valves and the piston in one of their limiting positions, and Figure 2 is a view similar to Figure 1 showing the valves and the piston in another extreme position. H 7 Referring moreparticularly to the drawings, A represents a cylinder of a rock drill having a piston chamber B in which is disposed a reciprocatory piston C. The piston C has a reduced extension D for delivering '3 blows to a working implement, such as adrill steel E supported and-guided by the front end of the drill. In the construction shown the cylinder A has a free exhaust port F which is controlled by the piston C.

For simplicity of illustration, the cylinder A is shown as having an integral valve chest G in which is formed a valve chamber H having enlarged pressure chambers J and K at its forward and rearward ends respectively.

The bore comprising the valve chamber I-I may extend entirely through the valve chest Gr and in the ends thereof are disposed closures in the formof hollow plugs L which are held securely in position by a bolt O pro- ;is threaded into the valve chest G for introducing pressure fluid into the intermediate L are clamped in position.

vided with a nut or nuts P whereby theplugs J Pressure fluid for actuating the drill may be conveyed froma suitable source of supply (not shown) through a connection Q, which or restricted portion B "of the valve chamber From opposite ends of the restrictedpors A tion R of the valve chamberlead inlet passages S and T to the piston chamber B. The

inlet passage S leads from the forward end of the restricted portion R of the valve chamber to the corresponding end of the piston chamber, and the inlet passage-T leads from the rearward end of the restricted portion R to the rearward end of the piston chamber.

The admission of pressure fluid to the front end of the piston chamber Bv is controlled by a distributing valve U which is ofthe dif ferential type and has a head V which lies in the pressure chamber J and an integral extension W which extends into the forward end of the restrictedportionR. A similar valve X is disposed in the pressure chamber K and has .a head Y in the pressure chamber K and an extension Z which extends into the rearward end of the restricted portion R and controls the inlet passage T. Due to this arrangement of'the valves Uand X the opa.

posing or innermost pressure surfaces b1; are

constantly exposed to pressure fluid in, the,

Valve .chamber H tending to open the valves.

' The outermost ends of the valves U and X constitute pressure surfaces 0 against, which pressure fluid may act intermittently for closing the valves. The admission ofsuch pressure fluid into the pressure chambers'lJ and K is in this instance controlled by the piston C which overruns tripper ports d ande. 7

The tripper port d leads from a point in the piston chamber B rearwardly of the free exhaust port F to the front end of the pressure chamber J and the tripper passage e v leads from a point forwardly of the free exhaust port F to the rearward end of the pressure chamber K. The tripper passages d and@ are in constant communication with the-valve chamber H throughleak passages f and g in the valve chest G so that pressure fluid will be constantly flowing into the tripper passages. 1

V In order to partiallyrelieve the compression inthefends-o'f the piston chamber B, a compression relief passageh' is formed in the valve chest G to lead from the inlet passage to the pressure chamberK. Thereliet passage h opens into the pressure chamber K at a point intermediate the ends thereof so that it may be covered by the head Y of the valve chamber J for relieving the compression in the rearward end ofthe piston chamber.

The reliefpassage jals'o opens into the pressurecham ber -J. at apoint intermediate the endsso that. 'in thef closed position of the "valve U, the head Y of said valve will close thesaid passage y'Q Inthe innermost ends of the pressure chambers and K are vents k and 0 res aectively for conveying the com- P Q iOniflOWing from the; pressure chamber to the atmosphere; I

I The operation of the device is as follows: With the valves U and X and the piston C in the positions illustrated in Figure '1,pressure fluid will flow from the valve chamber through the inlet passage T into the rearward end of the piston chamber B to impel the piston C forwardly; While the piston C is in the rearward .end of the pistonchamher, it covers the tripper passa ed sothat pressure fluid flowing through t e'leak passage 7 into said tripper passage and mm the face 0 of the valve .U to holdsaid valve closed. Pressure fluid will of, course also be flowing through the leak passage 9 and the tripper passage 6, but sincethe tripper passage je isjin directcommunication with the main exhaust portF, the pressure fluid in the tripperpassage e'will be ineffective to move the valve X, against the full line pressure acting against the pressure surface 7) for holdjing the valve X open.

i Asthe piston C proceeds in a forwardlydi- 'rection, the compression in the'fro'nt end of "the piston chamber will flow through the inlet passage Sand the compression relief pasfthrough the vent 0.

sage it into the pressure chamberK from when'cefit willescape to' the vatmosphere Ataabout the time the piston uncovers the tripper passage d, it will cover the tripper-passage e and pressure fluid will then immediately flow into the pressure chamber Kto actjagainst the pressure surfaceso of the valveX for closing said valve. Imme- I located, chamber J will act against the pressuresurdiately thereafter the main exhaust port-F will be uncovered by the piston and the pressure. fluid utilized for actuating the piston C forwardly, together with the pressure fluid acting against the pressure surface 0 of the valve U willthence escape to the atmosphere. I In these positions of the piston C and the valve U, the live-pressure fluid in thevalve chamber H, acting'on the pressure surface I) of the valve U will open saidvalve and pres- .75 sure fluid will then flow through-the inlet passage S into the front end of the piston chamber B to retract the piston. Meanwhile the valve X will be held closed. by'the pressure fluid flowing throughtheleak passage' 0 9" andthe tripper passage 6 into the'outer end oithe pressure chamber K.

During the rearward movement of the piston G, the tripperpassage d will be covered by the piston so that the pressure fluid flowg5 ing-into the. said tripper passage from-theleak'passa'ge fwill act against-the pressure surface '0' of thevalve' U for closing said valve; Continued rearward movementof the piston :C will place the tripper passage e into ao communication withthe exhaust port F so that "the pressure fluid used for holding the valve X closedmay then escape to the atmos I phere; When this occurs the pressure fluid acting against the pressure surfaced'of the 55 valve X will 'a'gain'open the valve.

After the plston C has covered the exhaust port F during the rearward travel of the piston, the compression in" the rearward end of the piston chamber B' will" flow throughthe inlet passageTthence through thecompresslon relietpassagej into the pressure chamber '5 from whence it will'escape to the atmosphere through the vent lo. "From this point on the cycle of operations may be re-los -The presentinvention has been found particularly eflicient for use indistributing the pressure fluid to rock drills of the hammer "type; 'Due to the arangementofthe various passages and ports, the pressure fluid which actu'ates the piston C may be used expans sively,'that is, the admissionof pressure fluid into the ends of the piston chamber may be cut ofl at any'suitable point in the travel of l'ls the piston before the exhaust port F is uncovered; As a result a heavy blow of-the Y piston C will be obtained and a great saving in the matter of pressure fluid consumption may be effected; I @320 We-claim: j s v. V 1. Ina fluid actuated rockv drill, the com bination ot'a'cylinder anda piston, an-exhaustport for the cylinder controlled by ,the piston,avalve chamber inletpassages leading from thevalve chamber to the'cylinder, valves in the ends of the valvechamber for controlling theinletpassages, said valves being constantlyexposed atone end to pressure fluid for actuating them in one direction,

tripper passages leading from the cylinder to the ends of the valve chamber andopening into the cylinder at points between the exhaust port andthe ends of the cylinder to enable said tripper passages to be covered by the piston before the piston uncovers the exhaust port, and leak passages constantly conveying pressure fluid into the tripper passages for throwing the valves in the other direction when the piston covers the tripper passages.

2. In a fluid actuated rock drill, the com bination of a cylinder and a piston, an ex-v haust port for the cylinder controlled by the piston, a valve chamber, inlet passages leading from the valve chamber to the cylinder, valves in the ends of the valve chamber for controlling the inlet passages, said valves being constantly exposed at one end to pressure fluid for actuating them in one direction, crossed tripper passages leading vfrom the ends of the valve chamber and opening into the cylinder at points intermediate the exhaust port and the ends of the cylinder, said tripper passages being covered by the piston before the piston uncovers the exhaust port, and leak passages'constantly conveying pressure fluid into the tripper passages for throwing the valves in the other direction when the piston covers the tripper passages.

3. In a fluid actuated rock drill, the combination of a cylinder and a piston, a main exhaust port for the cylinder controlled by the piston, a valve chamber having enlarged pressure chambers at its ends, inlet passages leading from the y alve chamber to the cylinder, compression relief passages leading from the inlet passages to the pressure chambers, vents leading from the pressure chambers for conveying compression from the said pressure chambers to the atmosphere, differential valves in the pressure chambers controlling the inlet passages and compression relief passages, said valves being constantly exposed to pressure fluid at their small ends for opening the valves, crossed tripper passages leading from the pressure chambers to the cylinder, and leak passages constantly conveying pressure fluid from the valve chamber into the tripper passages for closing the valves when the piston coversthe tripper passages.

4. In a fluid actuated rock drill, the combination of a cylinder and a piston therein, a main exhaust port for the cylindercontrolled by the piston, avalve chamber having ferential valves in the pressure chambers to control the inlet passages and having heads to control the relief passages, said valves being constantly exposed to pressure fluid at their small ends for opening the valves, crossed tripper passages leading from the pressure chambers to the cylinder, andleak passages constantly conveying pressure fluid from the valve chamber into the tripper passages for closing the valves when the piston covers the tripper passages.

In testimony whereof we have signed this specification. 7

WILLIAM A. SMITH, SR. WILLIAM A. SMITH, JR.

an intermediate restricted portion and enlarged pressure chambers at its ends, inlet passages leading from the restricted portion of the valve chamber to the ends of the cylinder, compression relief passages affording communication between the inlet passages and the pressure chambers, vents leading from the inner ends of the pressure chambers for conveying compression from the said pressure chambers to the atmosphere, dif- 

